Cam bolt systems provide a known manner of positionally adjusting linkages. In one known example, a cam bolt system is used in an automotive vehicle suspension linkage and provides the means to control alignment of the wheel tire assembly, i.e., camber, caster and/or toe alignment.
FIGS. 1-3 illustrate an example known cam bolt system 10 including a bolt 11 with a hexagonal head 14, a first shaft portion 12, with a circular cross section, extending a predetermined distance from the head 14, a second shaft portion 18 having a rounded rectangular cross section extending from the end of the first shaft portion 12 and a third shaft portion 20 having a circular cross section and threaded to receive nut 26.
A first cam 16 is fixedly attached to the first shaft portion 12 proximate to the head 14 and thus turns when the head 14 of the bolt 11 is turned. A second cam 22 has a rounded rectangular opening 24 of a shape to match and freely slide over second shaft portion 18. In an optimal system, cam 22 has little free play and is forced to turn with the bolt 11. The cams 16 and 22 operate together on two sets of cam followers (not shown) in a known manner (discussed in more detail below with reference to FIGS. 10 and 11) when the head 14 of the bolt 11 is turned. The result of the operation of the cams 16 and 22 on the cam followers (not shown) is that the position of the bolt 11 moves in the direction of arrows 13, positionally aligning the linkage or other system that is coupled to shaft portion 12 of the bolt 11.
When the bolt 11 is in the correct position, the nut 26 is tightened down, locking the bolt 11 and cams 16 and 22 in place. In the example shown, the nut 26 has a threaded portion 30 in the body 28 of the nut 26 and, on the end engaging the cam 22, a machined out opening 32, which tapers (reference 34) down to the threaded portion 30. The machined out portion 32 provides clearance for the end 31 of the nut 26 over the rounded rectangular shaped second shaft portion 18 of the bolt 11.
The cam bolt system shown in FIGS. 1-3 has numerous disadvantages including that it has two different cams 16, 22 and a bolt with three different cross section portions 12, 18 and 20, requiring machining of the bolt and leaving limited room for engagement of nut 26 on the bolt shaft portion 20. Further, care must be taken when attaching cam 16 to the shaft portion 12 so that cam 16 will be properly aligned with cam 22. This is necessary since cam 16 is not self aligning with respect to the bolt 11.
FIGS. 4-6 illustrate another prior art cam bolt system 40 including a bolt 41 having a hexagonal head 42 and a shaft comprising the spline 48, a portion 44 with a circular cross section and threaded and keyed portion 52. The threaded and keyed portion 52 is circular in cross section except for the key 58. The spline 48 retains the cam 46 on the shaft by an interference fit between the protrusions of the spline 48 and the perimeter 50 of the hole in the cam 46. The threaded portion of the shaft 52 is machined or broached to form a key or flat 58 for receiving cam 54 having an opening 60, which is round for most of its perimeter and has a flat 62 matching the key 58.
The cam bolt system 40 shown in FIGS. 4-6 operates in much the same way as the cam bolt system shown in FIGS. 1-3 with the two cams 46 and 54 turning when the bolt 41 is turned by the head 42. When the bolt 41 and cams 46 and 54 are properly positioned, the nut 56 is tightened retaining the cam bolt in place. A disadvantage of the system shown in FIGS. 4-6 is that, like the system shown in FIGS. 1-3, the bolt requires machining, in this case to create the key 58. Further the bolt shaft has three different sections, the spline 48, portion 44 with the circular cross section and the threaded and keyed portion 52. Additionally, like the system in FIGS. 1-3, the cam 46 is not self-aligning with respect to the bolt 41 and care must be taken when attaching cam 46 to the spline 48 so that cam 46 will be properly aligned with cam 54.
Also similar shown to the system shown in FIGS. 1-3, the system in FIGS. 4-6 requires two different cams, the upper cam 46 with a round hole to be press fit on the spline 48 and the lower cam 54 which must be able to slide over the threads and is fixed rotationally with respect to the bolt 41 by the key 58 and flat surface 62. It is noted that there is an inherent limited free play between the cam 54 and the bolt 41.
One disadvantage of both systems having two different cams is that one cam 22 (FIG. 1), 54 (FIG. 4) has play while the other cam 16 (FIG. 1), 46 (FIG. 4) does not have play with respect to the bolt, possibly resulting in slight misalignment of the two cams.